TAMPA – For four innings yesterday, Randy Johnson’s fastball looked great and his slider was tilting like a top. The Big Unit looked ready for Opening Day.

Until the fifth inning came around.

At that point, Johnson’s stamina was exposed by the Cardinals. His outing became a reminder that the regular season doesn’t begin on March 14.

The 42-year-old tossed four shutout frames of one-hit ball to begin his start. In the fifth, he was touched for two runs on four hits during the Yankees’ 4-3 loss.

“I really just kind of cruised along the first four innings,” Johnson said. “I decided to go back out there for the fifth, and then I hit a wall, I guess.”

Ron Guidry told Johnson he threw 36 pitches over four innings, but Johnson needed 31 more pitches in the fifth. “I may have made the mistake,” Joe Torre said. “I thought he was great (for four innings). He really did it quickly, too.”

While two runs in five innings doesn’t sound bad, Johnson was saved when center fielder Bubba Crosby backpedaled on the warning track and grabbed Scott Rolen’s flyout to end the fifth.

But for four frames, Johnson toyed with St. Louis. He said he was able to spot his fastball inside and liked the tilt on his slider. He had retired 11 in a row before things went south.

That’s when left-handed hitter Chris Duncan – who is the son of the Cardinals’ pitching coach – lined a solo homer over the right-field fence on a fat 2-and-0 fastball. Things snowballed, as Johnson put it.

Johnson feels his stamina will come along this month, as will his velocity. So things are progressing normally.

“For the most part, I felt very comfortable with the way I pitched today,” he said. “There were some easy innings. Overall, I felt pretty good. I got a little tired, for whatever reason.”

*

DH Jason Giambi (left calf) batted third, going 0-for-2 with a sac fly. “It’s very good,” Giambi said. “My only concern was getting out of the box, pushing out of the box. I’m fine. I was happy where my swing was at and the passes I took today. I was on pretty much everything, so I didn’t really miss a beat.”

Giambi will travel to Kissimmee today, where he’ll likely DH. Mariano Rivera and Kyle Farnsworth worked scoreless innings. Tanyon Sturtze and Mike Myers allowed a run apiece in the eighth and ninth. Robinson Cano was 2-for-4 with a solo homer.